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## [TowerTalk] Voltage vs Current feed

 To: [TowerTalk] Voltage vs Current feed alwilliams@olywa.net (Al Williams) Mon, 15 Oct 2001 21:59:50 -0700
 ```> If we measure and mark a wire that is one wavelength long the starting end > will be marked 0 degree point. At the quarter way point marked 90 degrees. > At the half way point marked 180 degrees. At the three quarter point marked > 270 degrees. At the end of the wire marked 360 degrees which is the full > wave point. If we had a way to measure what was going on at these five > points we would find that at the 0,180 and 360 degree points the voltage is > the highest then any other point along the wire. We would also find that at > the 90 and 270 degree points the current is the highest then at any other > point on the wire. Where the voltage is highest the current is lowest or > zero, where the current is highest the voltage is lowest or zero. > By feeding this wire at the points that the voltage is the highest > (0,180,360 degrees) this is called a voltage feed. By feeding this wire at > the points that the current is the highest (90,270 degrees) this is called > a current feed. Am I correct? Because of the open circuit (usually) at the far end of the antenna, the current must be zero throughout a cycle. If this is true, it seems to make sense to begin analysis starting at the far end and work back to the source using the thoughts expressed in the above posting. The feed then can be seen to be a function of antenna length. Do standing waves alter this observation? k7puc k7puc List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems, Trylon Titan towers, coax, hardline and more. Also check out our self supporting towers up to 100 feet for under \$1500!! http://www.anwireless.com ----- FAQ on WWW: http://www.contesting.com/FAQ/towertalk Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: owner-towertalk@contesting.com ```
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